The man in the red pants and white shirt doing crazy things on and around the finishing green at Medinah was long regarded on the PGA Tour as being serious as an accountant on tax day — stoic, almost robotic.

And then, in one swooping 45-foot putt, that image disappeared forever, replaced by one of the most exciting 18th-hole moments in U.S. Open history.

Hale Irwin had not even play golf full time on the PGA Tour for five years (1985-89), instead focusing on his course architectural business.

He returned in 1990, but he knew his 10-year exemption had run out and that if he wanted to return to the national open he would have to do it through U.S. Open sectional qualifying.

The USGA bailed him out, granting him a special exemption to play at Medinah. And Irwin sure made it look like a wise decision.

Needing something dramatic on the final hole Sunday just to force a playoff, Irwin surveyed the long birdie putt from the front of the green. He stroked it, and it continued to track right at the back-left pin location.

Once it dropped in, Irwin joyously raised his arms, delivered four fist-pumps and took off on a jog toward the right-side gallery.

It was there he started giving out high-fives to fans — all before returning to the green for a finishing kiss and wave to whoever was watching.

That raw, emotional display surprised a lot of onlookers — something Irwin, a former defensive back at Colorado, addressed months later to the Baltimore Sun.

“There were a lot of images out there, but I didn’t fit any of them,” Irwin said. “My game was methodical. I didn’t have that glamorous reputation behind me. I was starting from scratch. I didn’t fit the mold of what a professional golfer was supposed to be. My personality sat on the back shelf.”

That putt got Irwin into an 18-hole playoff with Mike Donald, a son of an auto mechanic who occasionally sold flowers and umpired baseball games when his PGA Tour career went south.

Donald led by two strokes with three holes remaining in the playoff. Irwin cut it in half with a birdie at the 16th hole — and it completely went away after Donald’s 15-foot putt to save par at No. 18 grazed the right edge. Both golfers shot 74.

On the first extra hole — No. 19 — Donald missed a 30-footer for birdie, and Irwin won it with a 10-footer from behind the hole.

At 45 years, 15 days old, Irwin became the oldest U.S. Open winner in history, eclipsing Raymond Floyd’s mark by 15 months. Floyd won in 1986.

And Irwin is one of six golfers to ever win three or more U.S. Open titles.

A pair of high-profile amateur golfers — Phil Mickelson and David Duval — made their national open debuts that week. Mickelson placed 29th; Duval 56th.